Inositol 1,4,5-Triphosphate Receptor Protein Immunohistochemistry of Cerebellar Purkinje Cells in Two Dogs with Hypoglycemia

Abstract

Immunohistochemical study was performed on cerebellar Purkinje cells of two dogs with hypoglycemia using an antibody against the inositol 1,4,5-triphosphate receptor that is identical to the cerebellar Purkinje cell glycoprotein P400 (P400/InsP3R). In the cerebellar neocortex of an acute case of hypoglycemia, the P400/InsP3R staining of hypoglycemic Purkinje cells was heterogeneous: some peripheral dendrites, including spiny branchlets, were negative and others were stained with various intensities, although Purkinje cells were morphologically intact by hematoxylin and eosin (HE) stain. In a chronic case of hypoglycemia, almost all the dendrites of Purkinje cells of both the neo- and archicortex of the cerebellum were not stained with the P400/InsP3R antibody. This is in contrast to the normal dog where Purkinje cell bodies, axons, and dendrites, including spiny branchlets, are intensely stained by the P400/InsP3R antibody. These results suggest that P400/InsP3R immunolabeling of Purkinje cells decreased, despite their morphology being preserved by HE stain, and that the function of P400/InsP3R, especially in spiny branchlets that receive inputs originating from axon terminals of parallel fibers, may be impaired in hypoglycemia.